Thunderstorms/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby Tim is holding a kite and looking out his window as a thunderstorm begins. TIM: Well, that wrecks that plan. Moby stands nearby. He is holding a cardboard box filled with letters. MOBY: Beep. TIM: Hey, good idea. I'll just pick one at random. Tim takes an envelope from the box and examines it. TIM: Hey, what do you know? Tim reads from a typed letter. TIM: Dear Tim and Moby, What is lightning, and what happens during a thunderstorm? From, Matthew. TIM: Well, it all comes from clouds. Storm clouds, as well as regular clouds, form when warm, humid air rises and cools. An animation shows humidity rising from the ground and forming a cloud high in the air. TIM: As the air loses heat energy, the water vapor condenses and you get clouds. An animation shows water vapor in the form of hazy orbs condensing to smaller opaque orbs. TIM: Storms can develop when the clouds cool enough so that rain droplets or ice crystals form. The sky darkens to indicate cooling as a cloud hangs in the sky. TIM: Clouds get so heavy with moisture that some falls down as precipitation, another word for rain or snow or hail. An animation shows rainfall. TIM: Lightning is created by static electricity. Strong air currents inside the storm clouds cause static charges to build up as the air molecules rub up against each other. An animation shows circular wind currents inside a rain cloud causing air molecules to rub against each other. TIM: This difference in electrical charge can correct itself in a couple of ways. Sometimes, an arc of electricity can occur inside the cloud itself as the charges equalize. This is called sheet lightning. An animation shows lightening flashing within a raincloud, as Tim describes. TIM: The ground, which is positively charged, can also attract lightning strikes. A zig-zag bolt of electricity called the leader stroke arcs from the cloud to the ground. An animation shows lightning arcing from a cloud to the ground. The ground has plus symbols to indicate it is positively charged. TIM: The ground answers with a bright return stroke that continues up to the cloud. The animation shows the return stroke making the zig-zag bolt brighter as it moved from the ground to the cloud as Tim describes. TIM: Electricity likes to take the easiest possible path, so the lightning is jagged as it finds its way through the atmosphere. Jagged lightning bolts arc from the cloud toward the ground, which answers with a return stroke. TIM: The whole thing is sort of like when you rub your feet on a carpet and get shocked by touching a doorknob, but on a much larger scale. Images show someone wearing socks rubbing their feet on a carpet. Another image shows that person's hand receiving a shock as it touches a doorknob. TIM: Lightning can heat the surrounding air to over 30,000 degrees Celsius. The surrounding air rapidly expands and generates an immense shock wave that you hear as thunder. An animation shows a lightning bolt producing heat. Then thunder crashes. Moby cringes, face-down on the floor, with his hands over his ears. TIM: Because the speed of light is so fast, lightning can be seen almost instantly. However, sound only travels about one kilometer every three seconds. That means that if you hear thunder nine seconds after you see the lightning, the lightning is about three kilometers away. An animation shows three lightning bolts moving from a storm cloud to the ground. About nine seconds later, thunder roars. TIM: If you see and hear the thunder and lightning together, that means the storm is right on top of you, and you should seek shelter. A large lightning bolt moves from the cloud to the ground. Thunder sounds at the same time. TIM: A bolt of lightning can be deadly, so it's really important to be safe. If you can't get indoors, move into an open space and squat low on the ground. Being in a car is pretty safe, because the metal exterior will conduct any lightning strikes directly into the ground. Moby and Tim are in a car during a storm. Moby reaches over and zaps Tim's face with static electricity from his finger. TIM: Ow. Stay away from water, tall structures and trees, and metal things, like golf clubs or Moby. Images show a puddle, a tall metal tower next to a tree, golf clubs, and Moby. MOBY: Beep. TIM: Well, a lightning rod is a copper rod placed at the top of a building, and connected to the ground by cables. An animation shows a lightning rod atop a skyscraper. A cable is placed as Tim describes. TIM: It provides an easy, safe path for the lightning to take to the earth so the building isn't damaged. Lightning hits the lightning rod, and a charge moves down the cable to the ground. MOBY: Beep. Moby now stands next to Tim. Moby has a lightning rod on his head. TIM: That's not such a good idea. Moby walks out into the thunderstorm with the lightning rod still on his head. Tim remains in the house and calls to Moby through an open window. TIM: Yeah. Moby, that's not gonna work unless you connect it to the— A large, loud thunderbolt crashes. Tim cringes. TIM: ...ground. MOBY: Beep. Category:BrainPOP Transcripts